Air-brake system.



A. DOAN.

lAIR BRAKE SYSTEM.

APPLICATION FILED NOV. 18, 1909. A 9?3,179, A 5 Patented 00t.18,1910.

THE Nlmls rlnrns co.. wAaRlNuroN, n. c.

ARTHUR DOAN, OF ELMHURST, CALIFORNIA.

AIR-BRAKE SYSTEM.

etarra.

Application filed November 18, 1909.

To all whome't may concern:

Be it known that I, ARTHUR DoAN, citizen of the United States, residing at Elmhurst, in the county of Alameda and State of California, have invented new and useful Improvements in Air-Brake Systems, of which the following is a specification.

This invention relates to air-brake systems, and pertains particularly to automatic safety appliances for use in railway brake systems.

'Ihe objects of my invention are to provide an automatic brake applying apparatus of extreme simplicity; to provide in conjunction with the usual manually controlled air-brake system a safety device perfectly automatic in operation; to provide a safety attachment inexpensive in construction which may be readily connected to any standard air-brake system; and also to provide an appliance whose action is directly controlled by the pressure of the brake-operating fluid in the train line.

The invention consists of the parts and the construction and combination of parts as hereinafter more fully described and claimed, having reference to the accompanying drawings, in which the figure is a diagrammatic plan of the appliance, with the safety device in section.

A is the train-line which carries the air or other fluid under pressure from the cab on the engine back through the train of cars, the flow of air through the train-line being suitably controlled to aetuate the brakes.

lVhile my invention is susceptible of a variety of constructions and arrangements, I have shown in the present instance a high pressure air reservoir or reserve high pressure tank 2, suitably supported on a car and connected by a pipe 3, in which is a checkvalve 4, to the train-line A. From the trainline A fluid under pressure may pass the check valve 4 and enter the reservoir 2, so as normally to maintain in reservoir 2 a reserve of fluid under maximum train-like pressure. In the event, however, of a reduction of pressure in the train-line A the valve 4 prevents the fluid in the high pressure reservoir 2 from escaping back through pipe 3 to the train-line A, and when needed the extra pressure in reservoir 2 is available for operating the brakes in the manner about to be described.

6 is a brake cylinder connected by means Specification of Letters Eatent.

Patented Get. 18, 1910.

serial No. 528,645.

of the pipe sections 7 7 to the usual triple valve 8 which is controlled by the engineer through the instrumentality of the fluid in the train-line A.

The operating fluid is allowed to pass from train-line A through a pipe 9 and the triple valve 8 in the usual manner into a brake-reservoir or auxiliary 10, from which it may pass through the triple valve 8 and connect-ions 7-7 to effect the operations of a. brakepiston in the cylinder 6. Fr quently, however, the rapid, successive applications of the brakes on a train, as when descending a grade, or traversing crossings or switches, cause the pressure of fluid in the train-line and brake reservoir to become so greatly diminished that sufficient force cannot be exerted upon the brakes to check the speed of the train, and unless the pressure is quickly built up by the compressor a runaway train is the inevitable result.

Sometimes when a train is climbing steep grades the couplings part, in which case one section of the train is entirely disconnected from any means for rebuilding the pressure in the train-line A, with consequent serious wrecks and fatalities. Therefore, for the purpose of avoiding such a failure of the brakes and to insure their positive application at such critical occasions, I provide a relatively small, simple device interposed between the high pressure tank 2 and the brake cylinder G, whereby on the decrease of pressure in the Atrain line below a point sufficient to operate the brakes effectively, the extra pressure in tank 2 will be available. As shown, a valve cylinder 11 is connected at its upper end by a suitable pipe 12, with the reservoir 2; and the lower enlarged portion 13 of the cylinder is directly in communication with the train line A through the pipe 14.

`Within the upper smaller chamber of the cylinder 11 is slidable a suitable piston valve 15 provided with a transverse port 16 adapted, with the piston in one position, normally to be in register with the pipes 7 -7 which are tapped into the cylinder 11, thus permit-ting a free flow of fluid from the brake reservoir 10 to the brake cylinder 6. Moving piston valve 15 in the opposite direction uncovers a port 20 to bring the high pressure reservoir 2 into communication with the brake cylinder 6. The lower end of the piston 15 is reduced or provided with the-high pressure reservoir, means by which y through port 16.

against the stop 18 and ltheport lrregisters with the pipesJT-T, so that ordinarily with a normally eiiective pressure in the train line the brakes are operated from the train line, through the triple valve and the high pressure lreservoir 2 is cut oi from the brake cylinder.

lf for any cause whatsoever pressure is abnormally reduced in the train-line A, the reserve pressure of fluid in the highpressure reservoir 2 will act immediatelyupon the upper end of piston valve 15, forcing it to:

traverse the cylinder 11 and by so doing will uncover port 20 by ,which-communicationwill beestablished, through duct 21 inthe side of cylinder 11, with the brake-cylinder,V (3 and by this Vmeans a pressure equal to. thatl,

of the normal maximum train-line A is eX- lerted to apply the brakes, and this irrespective of the pressure or lack; of pressure in:

flineand also having acon-nection with the brake cylinder, another connectionbetween thetrain line andy brake reservoir 10 after the piston llonce passes the opening or port. 2O.` `The stop plate 1S limits the travel of the :piston 15, and when pressure is again built up to normal or maximum in the traina line A it will act upon the head- 19 to return Athe piston 15 to allow of the normal action of the triple-valve 8- and `reservoir 10 Simultaneously ywith the increase of pressure inthe train-line A the charge in the reservoir 2 will be replenished f and the pressurebuilt up in readiness to be eective againthe instant an abnormal re-1 ductionfof pressureagainst thei head 19r occurs. Therefore, it will be noticed that I have provided ai device of simple-construc-r A vtion in which there is but one movable ele- `ment and one maincasting, to wit, the cyle inder 11.7 No tine adJustments are required.

and the device is.entirelyautomatic.

.Ha-ving thus described my invent-ion,'what I claim as new and desire to secure b y Letters-Patent, is

1. The.coinbination in an air brake system, of a train-linega brake cylinder, a, high `pressure reservoir connected with. the train-- line and also having .a iuid connection with 4the brake cylinder, a valve cylinder in the vconnection betweeiithe brake cylinder and the high pressure reservoir,.a piston valve in said valve cylinder, one end of said piston;

valve subject constantly tothe pressure in a difference in` pressure between thehigh pressure'reservoir and train-line results in,

the movement of said piston valve to admit .Huid from the high pressure reservoir to the brake cylinder, and a triple valve having luid connections with the train-line and with the brake cylinder, said connections between the triple valve and brake cylinder being controlled by said piston valve.

2. The combination in an air brake system, of a train-line, a brake cylinder, auxiliary reservoir, triple valve, connections between the train-line through the'triple valve and auxiliary reservoir to the brake-cylinlder, a by-pass connection between the trainl`line and brake cylinder around -the triple valve, a high .pressure reservoir in said by` Vpass connection and chargeable from the train line, and a piston valve'interposable in said by-passand in the connections between the train-line and triple valve, said piston valve. permitting flow from the train-line through the triple valve to the brake cyldersiniultaneously cutting off communication through the by-pass betweeni the high pressure reservoir and brake-cylinder, land means for operating the piston valve by the differential action4 of the train-line and high -pressure cylinder pressures.

3. The combination in an air brake system, of a train-line, a brake cylinder, a high pressure reservoir connected with the trainthe train line and brake cylinder, and a valve common to said last named connection and to the connection betweenthehigh pressure reservoir and brake cylinder by which one of saidconnections will be open when -the other is closed, and vice versa, and ,means by which said valve is operated through the differential action oi' pressures in the train lineand high pressure reservoir.

et., In an air brake system, vthe combination of a train-line, a brake cylinder, a high pressure reservoir connected with the train line, a valve cylinder, a diierential piston in the cylinder, a connection between one end of, the cylinder and the train line, and a connection between the other end of the cyl- Ainder .and the -high pressure i'eservoir, said valve being 4opei'able bythe dierential action ofthe pressures in the train line and ,highfpi-essure reservoir, a connection between the brake cylinder and the end of the valve cylinder which isconnected witlrthe highpressure reservoir, said connection between the brake cylinder and-valve cylinder being' normally closed by said valveand a connection between thetrain line and'brale cylinder.

5. Air-automatic air-brake-system comprising, in combination, a `train-line, a brake-cylinder, a brake-reservoir, a connection'betweenv said cylinder and reservoir, a high pressure reservoir connected with: said train-line, `and means directly. interposed in the connection between the brake-cylinder und the brake reservoir through which Colnn'nilneuton muy be established bet-Ween the high pressure reservoir and the brake ey]- inder, said means including a piston operable by the difference in pressure in the train-line and in the high pressure reservoir.

n testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

ARTHUR DOAN. vWitnesses FREDERICK E. MAYNARD, CHARLES A. PENFIELD. 

